Process for the conversion of hydrocarbons



June 6, 1933- G. s. DUNHAM PROCESS FOR THE couvmnsron 0F mmaocmuonsFiled Jan. 31, 1950 Rm MY m M N (R En 0 mm n f 5 OJY W W a m PatentedJune 6, 1933 UNITED STATES PATEN'D orr cs GEORGE S. DURHAM, FORT WORTH,TEXAS, ASSIGNOB TO SOCONY-VACUUM CORPORA- TION, OF NEW YORK, N. Y., ACORPORATION OF NEW YORK PROCESS FOR THE CONVERSION OF HYDBOCARBONSApplication filed January 81, 1830. Serial No. 424,802.

The present application relates to processes for the conversion anddistillation of hydrocarbons and has to do particularly with a processfor the production, conversion, and recovery of commercial quantities oflow boiling products from crude petroleum fractions, or in general fromany liquid of liquefiable hydrocarbon compound 9 or mixture whichcontains or is capable of tion.

The foregoing advantages and purposes are largely effected by means ofthe combinations, arrangements, and operative relationship of processsteps clothed in appropriate apparatus, described and shown in thefollowing specification and the drawing which is made a part thereof.

The drawing is adiagrammatic view, indicating a preferred combination,arrangement, and operative sequence and relation .by means of which theprocess may be conducted. While the drawing indicates a preferredembodiment, together with certain modifications, it will be understoodthat the particular embodiment here shown is largely illustrative.

In the drawing, directions of flow are indicated by arrows "placed uponthe lines, and

5 valves by the conventional cross mark placed upon the line valved.

Referring now to the drawing, charge oil is taken from tank 1 by pump 2,and delivered through line 3 to exchangers 4, 5, and 6, each of which isso piped that any amount of bypassing may be practiced as desired, whereit gains heat from the material with which it is therein placed in heatexchange relationship. After having been heated by heat exchange, thecharge oil is delivered by line 7 into fractionator 8. In enteringfractionator 8 it may enter upon one of the lower fractionating trayswith which the fractionator would be equipped, or it may pass directlyjto the storage space provided at the bottom of such fractionators.

In the bottom of fractionator 8 the incoming fresh charge meets and iscombined with the unconverted products of a cracking step laterexplained, which have been reduced to liquid form in fractionator 8. Thecombined charge and unconverted oil are withdrawn from 8 by pump 9 andpassed through coils 10 in furnace 11, where the oil is subjected tocracking temperatures, while being held under a pressure suflicientlygreat to maintain the stream of oil at a density approaching that of aliquid. This pressure is released by valve 12 to substantiallyatmospheric pressure, and the products of the cracking reaction flow tovaporizer 13 where, by means of their contained heat, all products oflower boiling point than fuel oil are vaporized, to leave by vapor line14, and enter fractionator 8. The fuel oil residue remaining invaporizer 13 is withdrawn by line 15, passing through exchanger 6,cooler 16 and line 17 to storage.

The vapors entering fractionator 8 by line 14 consist of crackedproducts of the nature of the desired gasoline, gas, and the productswhich passed through the cracking zone .without being changed. Allconverted and sar 1 1 1 order to better control the operation offractionator 8 and to enable it to handle a greatly increased duty,there is withdrawn by line 29 from the bottom of fractionator 8 aportion of the oil therein. This oil is passed through exchanger andcooling coil 30, whence pump 31 forces it through line 32 to beintroduced into vapor line 14 just previous to its entry to fractionator8. Thus by an extraction of heat from fractionator 8 its capacity isincreased.

Uncondensed gases in line 21 contain a V considerable amount ofrecoverable gasoline,

so they are delivered preferably by means of booster 33, into absorber34. The cool gas oil from coil 30 and pump 31 is a suitable absorbentmedium for this gasoline, and

so is introduced into the absorber through line 35, and when enriched isreturned to the system by pump 36 and line 37, where it is preferablyreintroduced to line 32 or its branches, as shown. Stripped fixedgasesare removed to fuel usage by line 38. Variations in the supply of gasoil by pump 31,

if in excess of requirements, may be vented by connection 39 and, if forany reason such as failure of pump, coil or exchan er, the suppl shouldbe insuflicient or insu ciently cool a portion of the charge oilsuflicient to make up the deficiency may be introduced by pump 40.

Under some conditions of operation the temperature desired at the exitfrom heater 10 may be so great that undesirable portions of the crackedfuel oil residue may be vapprized, or in extreme cases the residue maydriven to dryness, causing sto page of the vaporizer and shut down of te equipment. Thism'a be controlled by several means. Cooled uel oilproduced by the unit can be returned to vaporizer 13 by pump 41 and line42, or pump 41 can handle cold fuel oil from an outside source drawnthrough line 43, or cool gas oil from line 32 may be introduced throughline 44. The necessity for the use of any of these steps, or theparticular step found best to use, varies with the stock charged andproduct desired, and any of them, or any combination of them, may befound necessary or desirable to best operation.

As one example of the various operations that may be performed by meansof this process and apparatus, an amount of 30 A. P. I. gas oilcommensurate with the size of the apparatus may be charged through theexchanger system, entering the fractionator at any temperature fromatmospheric to around 500 F. depending upon the amount of exchangeheating made use of. The char e, combined with material condensed in theractionator, is heated in furnace 11 to temperatures of sayapproximately 900 F. at exit, and held under an exit pressure of sayapproximately 350 pounds per square inch, the degree of temperature andpressure varyin from one charging stock to another but being of thegeneral magnitudes just stated for a 30 A. P. 1. gas oil derived fromNorth Texas crude oil. This pressure is decreased to the pressureobtaining in the vaporizer at valve 12. The pressure in vaporizer 13 issubstantially atmospheric, i. e., atmospheric increased only by theresistance of apparatus between the vaporizer and final release toatmosphere, there being no constrictions or other valve or device forartificially raising this resistance. Relative to the other pressures inthe system this is, for all practical purposes, substantiallyatmospheric.

The liquid products of the cracking reaction remaining from thevaporization and drawn oil to storage amount to approximately 35% of theoriginally charged fresh gas oil.

From the vapor passing to the fractionator there are separatedapproximatel 55% of gasoline-like substances and 8% o gases normallyuncondensable, percentages being calculated against originally chargedfresh gas oil.

In the specific example of operation given above, there is withdrawnfrom the bottom of the fractionator by line 29 an amount of gas oilnearly twice as great as the fresh charge which, after cooling, isdivided, approximately one-third passin over absorber 34 and the restbeing intro uced to vapor line 14. The actual amount of this circulationwill vary with the stock charged and with the equipment used, but to fargreater extent with the equipment, and except in connection with theexample given, is incapable of specification.

Certain of the process steps disclosed are applicableto any process offractionation, and certain are applicable to many other processes ofconversion, as well as to the one shown and described.

I claim:

1. In a process of cracking oils which comprises subjecting oil tocracking conditions of temperature and pressure in a flowing restrictedstream, se arating the vaporous products of the reaction stream from theliquid products thereof in a separating zone, and passing all of thevaporous products of the reaction stream simultaneously into afractionating zone, therein to reduce a fractionator condensate liquidat the temperature existing in the bottom of the said fractionator and afractionator overhead comprising substantially the desired products ofthe reaction, that step which consists of removing a portion of thefractionator condensate, cooling it sufficiently to remove a substantialportion of its'sensible heat, preventing the direct return of heat soremoved to the fractionator, and introducing said cooled condensate'intophysical admixture with the vaporous products of the reaction zonebetween said separator and said fractionator, thereby to cool saidvapors before they are subjected to fractionation, whereby the relativevolume of vapors passing upward through the equilibrium zones of saidfractionator is decreased, and a fractionator of fixed vapor volumecapacity is enabled to handle a relatively increased amount of desiredreaction zone product.

2. The process of producin relatively low boiling point hydrocarbons romrelatively high boiling point hydrocarbons which comprises passingrelatively high boiling point hydrocarbons through a cracking zone andheating the same while in the cracking zone to effect a cracking of asubstantial portion of the hydrocarbons, passing the hydrocarbons fromthe cracking zone into a separating zone and thereinveflectingseparat1on of the same into vapors constituting all of the vaporsproduced by the heat applied to said hydrocarbons in the cracking zoneand a liquid residual oil, passing the said vapors from the separatingzone and into a fractionating' zone as a continuously flowing stream andeffecting in the fractionating zone initial fractionation of the totalvapors passed from the separating zone and the condensation of higherboiling point portions thereof to form a fractionator condensate havinga boiling point above the temperature existing at the bottom of thefractionation zone while the lower boiling pdint portions of said vaporsare permitted to pass through and out of said fractionating zoneuncondensed, substantially continuously withdrawing and cooling aportion of the said fractionator condensate having its boiling pointabove the temperature existing at the bottom of the fractionating zoneto remove therefrom a substantial uantity of sensible heat whilepreventing t e direct return of the heat thus removed to thefractionating zone, introducing fractionator condensate thus cooled intoadmixture with the vapors from the separating zone before they aresubjected to fractionation in said fractionating zone to effect thecooling of the said vapors, whereupon the previously cooled condensateis again collected in the fractionating zone together with additionalcondensate having a boiling point above the temperature existing at thebottom of the fractionating zone, the cooling of the vapors therebyreducing the relative amount of cooling which must be effected in saidfractionating operation, and reducing substantially the relative volumeof vapors existent within the fractionating operation, whereby the saidfractionating zone is capable of handlin a substantially increasedproduction of low boiling point bydrocarbons from the cracking zone.

3. The process of producing relatively low boiling point hydrocarbonsfrom relatively high boiling point hydrocarbons, which comprises passingrelatively high boiling point hydrocarbons through a cracking zone andheating the same while in the cracking zone to effect a cracking of asubstantial portion of the hydrocarbons, discharging the hydrocarbonsfrom the cracking zone in the form of a continuously flowing stream andseparating the same into vapors constituting all of the vapors producedby the heat applied to said hydrocarbons in the cracking zone and aliquid residual oil, passing said vapors from the separating zone andinto a fractionating zone as a continuously flowing stream and effectingin the fractionating zone initial fractionation of the total vaporspassed from the separating zone and the condensation of higher boilingpoint por-- tions thereof to form a fractionator condensate having aboiling point above the temperature existing at the bottom of thefractionating zone while the low boiling point portions of said vaporsare permitted to pass through and out of said fractionating zoneuncondensed, condensing and collecting the said lower boiling pointportions, passing the gases and vapors which still remain uncondensedinto an absorbing zone, withdrawing fractionator condensate having itsboiling point -above the temperature existing at the bottom of thefractionating zone from said fractionating zone, subjecting fractionatorcondensate thus withdrawn to cracking treatment in said cracking zonewith a fresh charge of relatively high boiling point hydrocarbons,substantially continuously cooling a further portion of the fractionatorcondensate withdrawn from the fractionating zone to remove therefrom asubstantial quantity of sensible heat, passing a portion of thefractionator condensate thus cooled into said absorbing zone intoadmixture with the aforesaid uncondensed gases and vapors entering saidzone to absorb hydrocarbon gases and vapors and then passing the saidcondensate thus enriched into admixture with the vapors which have beenseparated in said separating zone, before said vapors are subjected tofractionation, introducing a further portion of fractionator condensatethus cooled into admix-- ture with the vapors passed from the crackingzone after the vapors have been separated from the liquid residual oiland before they are subjected to fractionation in said fractionatingzone to effect a cooling of the said vapors, whereupon the previouslycooled condensate is again collected in the fractionating zone togetherwith additional condensate having a boiling point above the temperatureexisting at the bottom of the fractionating zone, the cooling of thevapors thereby reducing the relative amount of cooling which must beeffected in said fractionating operation, and reducing substantially therelative volume of vapors existent within the fractionating operation,whereby the said fractionating zone is capable of handling asubstantially increased production of low boilingpoint hydrocarbons fromthe cracking zone.

4. The process of producing relatively low boiling point hydrocarbonsfrom relatively high boiling point hydrocarbons, which comprises passingrelatively high boiling point hydrocarbons through a crackin zone in theform of a rapidly flowing reaction stream of restricted cross sectionalarea and heating the same while in the cracking zone to efiest acracking of a substantial portion of the hydrocarbons, maintaining apressure upon said reaction stream of at least the order of 350 lbs. persquare inch at the outlet end of the cracking zone, discharging thehydrocarbons from the cracking zone in the form of the rapidlycontinuously flowing stream into a separating zone wherein the velocityof the said hydrocarbons is initially check and said hydrocarbons areseparated into vapors and a liquid residual oil, releasing the pressureupon said hydrocarbons substantially concurrently with discharge thereofinto said separating zone so that the pressure in said separating zoneisabove atmospheric only by such an amount as is required to maintainthe flow of the hydrocarbons through the remainder of the process,passing sald vapors from the separating zone and into a fractionatingzone as a continuously flowing stream and efl'ecting condensation ofhigher boiling point portions thereof to form a fractionator condensatehaving a boiling point above the temperature existing at the bottom ofthe fractionating zone while the low boiling point portions of saidvapors are ermitted to pass through and out of said ractionating zone'uncondensed, condensing and collecting the said lower boiling pointportions of the vapors, withdrawing from said fractionating zonefractionator condensate having its boiling point above the temperatureexisting-at the bottom of the fractionating zone, subjectingfractionator condensate thus withdrawn to cracking treatment in saidcracking zone with a fresh charge of relatively high boiling pointhydrocarbons, substantially continuously withdrawing a further portionof the said fractionator condensate and cooling same to remove therefroma substantial quantity of sensible heat while avoiding any direct returnof the heat thus removed to the fractionating zone, introducingfraetionator condensate thus cooled into admixture with the vapors ofthe stream at the reduced pressure between the separating zone and thefractionating zone to effect cooling of the stream prior to its passageinto the fractionating zone whereupon the previously cooled condensateis again collected in the fractionating zone with additional condensatehaving a boiling point above the temperature existing at the bottom ofthe fractionating zone, the cooling of the stream thereby reducingsubsantially the relative amount of cooling which must be effected insaid fractionating operation, and reducing substantially the relativevolume of vapors existent within the fractionating operation, wherebythe said fractionating zone is capable of handling a substantiallyincreased production of low boiling point hydrocarbons from the crackingzone.

5. The process of producing low boiling point hydrocarbons fromrelatively high boiling point hydrocarbons which comprises passingrelatively high boiling point hydrocarbons in a stream through acracking zone and therein effecting a cracking of a substantial portionof the same, passing the stream of hydrocarbons from the cracking zoneinto a separating zone and effecting separation of the same into vaporsand a. liquid residual oil, passing said vapors from the separating zoneas a continuously flowing stream into a fractionating zone for effectinginitial fractionation of the vapors and condensation of higher boilingpoint portions thereof to form a fractionator condensate having aboiling point above the temperature existing at the bottom of thefractionating zone while the lower boilin point portions of said vaporsare permitted to pass through and out of said fractionating zoneuncondensed, condensing and colletting the said lower boiling pointportions of the vapors, withdrawing from said fractionating zonefractionator condensate having its boiling point above the temperatureexisting at the bottom of said zone, subjecting i'raetionator condensatethus withdrawn to cracking treatment in the said cracking zone with afresh charge of relatively high boiling point liquid hydrocarbons whichhave not previously been passed through the cracking zone, substantiallycontinuously withdrawing a further portion of the fractionatorcondensate and cooling same to remove therefrom a substantial quantityof sensible heat while avoiding any direct re-V turn of the heat thusremoved to the fractionating zone, introducing fractionator condensatethus cooled into admixture into the vapors of the stream between theseparating zone and the fractionating zone to effect the cooling of thestream prior to its passa e into the fractionating zone whereupon t epreviously cooled condensate is a ain collected in the fractionatingzone with additional condensate having a boiling point above thetemperature existing at the bottom of the fractionating zone, thecooling of the stream thereby reducing the relative amount of coolingwhich must be efi'ected in the said fractionating operation, andreducing substantially the relative volume of vapors existent within thefractionating operation, whereby the said fractionating zone is capableof handling a substantially increased production of low boiling pointhydrocarbons from the cracking zone.

In testimony whereof I aifix my signature.

GEORGE S. DUNHAM.

DISCLAIMER 1,913,049.-Ge0rge S. Dunham', Fort Worth, Tex. Pnoonss FORTHE CONVERSION OF HYDROCARBONS. Patent dated June 6, 1933. Disclaimerfiled July 3, 1935, by the assignee, Sammy-Vacuum Oil Company,Incorporated.

Hereby enters this disclaimer to claim 1 of said Letters Patent in itsentirety, and to exclude from the scope of claims 2 and 5 of saidLetters Patent all of the processes defined, excepting those wherein thesaid cracking of the hydrocarbons is carried out while the hydrocarbonsare conducted as a moving stream of relatively small cross section.

[Oficial Gazette July 30, 1935.]

tionating zone, introducing fractionator condensate thus cooled intoadmixture into the vapors of the stream between the separating zone andthe fractionating zone to effect the cooling of the stream prior to itspassa e into the fractionating zone whereupon t e previously cooledcondensate is a ain collected in the fractionating zone with additionalcondensate having a boiling point above the temperature existing at thebottom of the fractionating zone, the cooling of the stream therebyreducing the relative amount of cooling which must be efi'ected in thesaid fractionating operation, and reducing substantially the relativevolume of vapors existent within the fractionating operation, wherebythe said fractionating zone is capable of handling a substantiallyincreased production of low boiling point hydrocarbons from the crackingzone.

In testimony whereof I aifix my signature.

GEORGE S. DUNHAM.

DISCLAIMER 1,913,049.-Ge0rge S. Dunham', Fort Worth, Tex. Pnoonss FORTHE CONVERSION OF HYDROCARBONS. Patent dated June 6, 1933. Disclaimerfiled July 3, 1935, by the assignee, Sammy-Vacuum Oil Company,Incorporated.

Hereby enters this disclaimer to claim 1 of said Letters Patent in itsentirety, and to exclude from the scope of claims 2 and 5 of saidLetters Patent all of the processes defined, excepting those wherein thesaid cracking of the hydrocarbons is carried out while the hydrocarbonsare conducted as a moving stream of relatively small cross section.

[Oficial Gazette July 30, 1935.]

